Quick Hit: six years later, New Orleans still doesn’t have functional levees

According to Nola.com:

A new Army Corps of Engineers rating system for the nation’s levees is about to deliver a near-failing grade to New Orleans area dikes, despite the internationally acclaimed $10 billion effort to rebuild the system in the aftermath of Hurricane Katrina, corps officials have confirmed. Preliminary rankings obtained by The Times-Picayune show that the corps believes there’s still a significant risk of flooding from major hurricanes or river floods that are greater than the design heights of Mississippi River levees and hurricane levees on both the east and west banks. In both cases, the levees were rated Class II or “urgent (unsafe or potentially unsafe),” on a scale of I to V, with V representing normal or “adequately safe.”

Can someone please help me understand this?!